JPH0137802Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention relates to a hopper for foundry sand.

Prior Art When molding sand is mixed with water, clay or other binders, it is temporarily stored in a hopper. At that time, foundry sand is gradually introduced using a belt conveyor, etc., and is piled up in the hopper in a mountain shape with the center higher, so the sand with large grain size and coarse particles rolls down the mountain slope and collects on the periphery of the hopper. Since fine sand with small particle size remains in the hopper, the particle size distribution of the foundry sand inevitably becomes uneven within the hopper.

In a conventional hopper, the bottom surface becomes lower toward the center, and the outlet is provided in the center, so when sand is taken out from the outlet, the finer sand in the center is discharged first. The coarse sand at the periphery is then drained away.

If sand with different particle sizes are discharged unevenly over time, the molding sand will have to be mixed separately for coarse sand and fine sand, which will make it difficult to obtain stable bonding strength for molds and cores. This has caused some inconveniences, and also has the disadvantage that there is variation between products with rough surfaces and those with dense surfaces, and when the difference is significant, defective products are produced.

In order to solve this problem, conventionally, a plurality of hoppers are used with one discharge port in order to make the particle size of the sand taken out from the discharge port uniform. However, if the degree of sand accumulation in each hopper is the same, sand of different particle sizes will be discharged from the discharge port over time, so there is no effect in making the particle size mixture uniform, and it is difficult to use it effectively. This method had the disadvantage that it was necessary to vary the degree of sand accumulation in stages for each hopper, which was laborious and required careful attention.

In addition, partition plates are installed in stages at the top and bottom inside the hopper.
A hopper that prevents uneven particle size distribution while the foundry sand falls sequentially from the upper partition plate has been developed, but in such a hopper, uneven distribution of particle size occurs in each partition in the hopper. As a result, particle size uniformity was incomplete.

Purpose of the invention This invention solves the above-mentioned drawbacks of conventional hoppers, and aims to provide a hopper that can take out molding sand at a uniform particle size ratio over time.

Structure of the invention In other words, the structure of the present invention to achieve the above object is to arrange a plurality of hollow sand absorbing towers in a container at approximately equal area ratios, and The structure is such that the sand absorbing tower has openings all over the place for the sand to fall into, and the sand that has entered the sand absorbing tower is collected towards the outlet.

Embodiment The drawing shows an embodiment of this invention.The hopper has four sand absorption towers 2 erected in a container 1, and sand is collected from each sand absorption tower 2 under the container 1. It is provided with a discharge port 3 that flows downward.

The container 1 has a rectangular box shape, but the peripheral bottom wall 4 is sloped low toward the center, the central bottom wall 5 is raised in a pyramid shape, and the space between the sloped bottom walls 4 and 5 is V-shaped. It becomes a valley 8, and the valley 8 circulates in a rectangular shape.

The sand absorbing tower 2 is erected by passing the pipe 10 for the main pipe 12 through the lowest valley 8 at the bottom of the container 1 at each corner position of the circulation.
The upper end is sealed with a top wall 11, and a large number of openings 7 are provided evenly in a staggered manner on the sides. Main 12
are provided below the center of the container 1, and each pipe 10 is connected to the upper end. Below the main pipe 12 is provided a spout 13 through which the discharge port 3 opens, and between the main pipe 12 and the spout 13 a shutter 15 is provided so as to be openable and closable. and mouthpiece 1
3 is fixed.

When foundry sand is introduced into the hopper, the foundry sand is deposited in the container 1 and falls through the opening 7 to fill the branch pipe 10 and the main pipe 12. Then, when the shutter 15 is opened, each sand absorption tower 2
Sand is sucked through the opening 7 of the main pipe 12, and the sand is gathered up by the main pipe 12 and falls from the discharge port 3.

As for how the foundry sand accumulates in the container 1, as shown by the dashed line in Fig. 3, the center swells and the coarse sand rolls down the slope.
Coarse sand is concentrated at the periphery, and fine sand is concentrated at the center.

This uneven grain size distribution of the foundry sand within the container 1 is similar to the conventional hopper, but the sand absorption towers 2 are provided in each of the four radial directions from the center of the container 1, and each They are located in the middle between the center and the side wall 6, and are arranged in an approximately equal proportion of the area, and since many openings 7 are uniformly provided on the side of the sand absorbing tower 2, when the shutter 15 is opened, ,
Sand settles at an average level.

Therefore, uneven distribution of particle size does not occur in the container 1 during removal of foundry sand, and since sand is taken out evenly from various parts of the container 1, even if there is uneven distribution of particle size in the container 1 as described above. , foundry sand with the same particle size ratio can always be collected from the discharge port 3.

Furthermore, since the bottom of the container 1 is the lowest point at which the sand absorbing tower 2 is installed, all the foundry sand can be removed.

Effects of the invention As explained above, the hopper for foundry sand according to this invention has a plurality of hollow sand absorbing towers arranged in a container with approximately equal area ratio, and each sand absorbing tower is Since the openings for sand to fall into the container are uniformly provided on the side, the sand in the container is drawn out from various places evenly, and since the outlet is the same, it is possible to always take out the foundry sand with an even particle size ratio. It does not require any effort or attention to equalize the particle size ratio, and together with its simple structure, it exhibits a remarkable practical effect.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention; FIG. 1 is a partially cutaway perspective view of the hopper, and FIG. 2 is a perspective view of the hopper.
FIG. 3 is a cross-sectional view taken along the line B--B, and FIG. 4 is a cross-sectional view showing how sand falls into the sand absorption tower from the opening. 1... Container, 2... Sand absorbing tower, 3... Discharge port, 7... Opening.

Claims (1)

[Scope of utility model registration request] A plurality of hollow sand absorbing towers are arranged in a container with approximately equal area, and openings are evenly provided on the sides of the sand absorbing towers through which sand falls, and each sand absorbing tower is placed under the container. A hopper for foundry sand characterized by having an outlet through which sand flows down.